There are several iPhone apps available that transform your iPhone into a makeshift light meter. They work somewhat ok, all considered, but if you’ve been looking for a fancier solution involving your iPhone, one has finally arrived.
It’s called the Luxi, and is a small clip on accessory that decks out your iPhone with a round white diffusion dome. Well, that’s pretty much all the adapter is: a clip and a dome.
The dome is designed to rest securely over your iPhone’s front-facing camera. Once it’s in place, you boot up the free app that is offered with the device (or an existing light meter app you’re already using) and you’re good to go.
Extrasensory Devices, the company behind the Luxi, claims that the diffusion dome will lead to more accurate readings than if you use the front-facing camera by itself. It also reportedly delivers “comparable results” when pitted head-to-head with professional meters